This invention relates generally to insulated containers and, more particularly, to a shipping container that is especially useful in cooling and transporting thermally sensitive materials such as pharmaceuticals, organs, tissues and vaccines.
It is often desirable and necessary to cool or freeze a specimen in order to preserve it for storage or transport. However, a number of specimens are sensitive to, and can be damaged by, changes in temperature and freezing. The specimens contemplated for use with the present invention can be any material which it is desirable to protect and thermally insulate during transport. Examples of such specimens can be chemicals, organs, tissues, blood, vaccines, food products, or other such materials.
For example, freezing a specimen of equine (horse) semen for storage or shipment appears to damage the spermatozoa therein. As a result, the pregnancy rates achieved using frozen (and then thawed) equine semen is a relatively low 50-60 percent. In contrast, the pregnancy rates achieved using horse semen that has been cooled, but not frozen, can be 90 percent or higher.
And although cooling equine semen is more effective than freezing it, cooling can also result in damage to a specimen. If an equine semen specimen is cooled too rapidly, thermal shock can cause irreversible damage to the spermatozoa. On the other hand, if the specimen is cooled too slowly, the spermatozoa will be damaged by the prolonged exposure to high temperatures.
Accordingly, because the viability of a specimen (such as equine semen) can be affected by the rate at which it is cooled, there is a need for a storage and/or shipping device that can be used to cool a specimen at a controlled and consistent rate. In addition, once the specimen""s target temperature has been reached, the device should be able to maintain the specimen within a desired temperature range for extended periods of time, regardless of the ambient temperature outside the device.
In general, the present invention fulfills these needs by providing a device comprising an container having a base unit and a lid. The container is insulated, preferably through the use of vacuum insulation paneling.
A tray adapted to hold specimen jars or syringes is placed within the insulated container along with a coolant. To control the rate at which the coolant draws heat from the specimen, one or more competing heat sources are placed within the container along with the specimen and coolant. In the preferred embodiment, the competing heat source comprises expanded polystyrene panels coating the inner surface of the insulated container.